The microphone inside the casing usually has access to the surrounding air through a canal and an orifice in the casing of the communication device. If a sound tight fit between the orifice in the casing and the canal is not provided, there is a risk that sounds provided to the ear from a possible sound generating device in the casing may leek into the microphone canal and cause feed back problems. Further, an air and fluid tight fit between the orifice in the casing and the canal is advantageous, as this helps to prevent foreign substances such as sweat, salt or dust from entering or migrating into the casing, where such substances would harm the delicate electronic components of the device. In head worn communication devices it is also desired that the microphone opening in the casing should be as in inconspicuous as possible in order not to draw unnecessary attention to the device.